The U.S. military is currently employing a sensing technique to remotely monitor the air, in order to detect potentially life-threatening chemicals, pathogens and toxins. The idea was recently used as a source of inspiration, and turned into an instrument that could help probes "sniff" for extraterrestrial life on Mars and possibly everywhere else in our solar system.
The instrument is called the Bio-Indicator Lidar Instrument, or BILI. The NASA technologist in charge of the project formerly worked for a company developing the sensor; he had the idea from there, then turned it into a prototype at the Goddard Space Flight Center in Greenbelt, Maryland. Through his project, the scientist proved that the same principles used in identifying bio-hazards can be employed in spotting organic bio-signatures on other planets.
This is how Branimir Blagojevic came up with BILI, a fluorescence-based lidar, which is essentially a remote-sensing instrument using the principles of radars; however, instead of being operated through radio waves, the instruments use light to analyze the particles' composition in the atmosphere.
In the process of detecting chemicals in the Earth's atmosphere, NASA has utilized fluorescence instruments, but the technique hasn't yet been tested in planetary studies.
However, the team of scientists on the project is quite excited by the possibilities this instrument opens. The reason why it will be unique, aside from not being used anywhere else in the world, is that the small levels of complex organic materials will be instantly detected from a distance of a few hundred miles away.
The manner this instrument is built implies that it will autonomously look for bio-signatures in plumes, and it will manage to reach areas that can hardly be reached by a normal rover, the level of its analysis being both very precise in nature and very wide in practicality.
Moreover, due to the fact that the analysis will be carried out from a distance, the instrument will less likely contaminate the samples with other substances or materials that could influence the results and impair the analysis. Due to these qualities, the instrument represents a perfect complementary instrument. Used with point sensor-type spectrometers, which cannot measure the same amount of material as BILI.
The possibility of finding bio-signatures will significantly increase once this instrument will be out "sniffing" for extraterrestrial life forms, as it not only complements the other instruments already employed, but it also has a different detection mechanism, which will add plurality and perspective to the procedure of inspecting other planets for bio-signatures.